The study is fundamentally set forth as an efficacy study on the prevention of the development of diabetes mellitus and on the changes of the carbohydrate metabolism. The averages and proportions with their corresponding 95% confidence intervals for clinically relevant variables measured during the baseline evaluation will be obtained in a descriptive analysis. In order to evaluate the presence of differences between the groups, the Student's t test, the Mann-Whitney test, the CHI2 test or the Fisher´s exact test according to the variable under study will be used. A Linear multiple regression will be used with the purpose of comparing the treatment groups from baseline and its changes up to month end 6 of each treatment. The possibility of performing adjustments by required baseline parameters and risk factors and prior treatment in each one of the treatment groups is considered.